Treatment of rheumatoid arthritis and related diseases

ABSTRACT

It is believed that rheumatoid arthritis and related collagen and auto-immune diseases are an infection and that various species of free-living (limax) amoebae are the aetiological agent of these diseases. It has been discovered that certain nitroimidazole compounds, anti-mycotic drugs with anti-protozoal activity, are effective for the treatment of rheumatoid arthritis and other collagen and auto-immune (rheumatoid) diseases.

This is a division of application Ser. No. 935,401, filed Aug. 21, 1978.

BACKGROUND OF THE INVENTION

Men and other animals are continually exposed to infections andre-infection by various species and strains of free-living limax amoebaewhich can be detected in the faeces, nasopharynx and bronchi. In allparts of the world they form part of the environment. Experimentally inanimals they induce changes like those of collagen and auto-immunediseases and are characterized by vasculitis, myositis, hepatitis,pyelitis and splenomegaly. They can often be seen in the tissues ofanimals. Such animals show lymphadenopathy with the appearance like thatof human Hodgkin's disease or a state like that of advanced malignantdisease. These organism may also be recovered from all the tissues ofcases of collagen and auto-immune diseases and from human and manyanimal tumors and may also occur in the tissues of apparently healthyindividuals. They cannot be identified in ordinary sections, but can bedemonstrated by immunofluorescent methods.

The definite cause of rheumatoid arthritis is presently unknown.Rheumatoid arthritis is a crippling disease, characterized by theinflammation of several joints of the body, with swelling, pain andstiffness. Rheumatoid arthritis is a disorder that afflicts aboutfifteen million people in the Western World alone. Successful earlytreatment may avert the destructive, deforming phase of the disease.Therapy has been directed largely at non-specific suppression ofinflammatory and immunologic processes. Aspirin is the cornerstone oftherapy for rheumatoid arthritis and can reduce pain in a majority ofpatients in view of its analgesic action. Widespread interest inrheumatoid arthritis arose when Hench (1949) introduced cortisone intreatment. Chemical compounds which have been commonly used in treatingrheumatoid arthritis are corticosteroids, gold salts, antimalarialdrugs, immunosuppressive agents and a whole range of so-callednon-steroidal drugs, e.g. indomethacin, phenylacetic acid (Ibuprofen),propionic acid (Naproxen) and D-Penicillamine. Most of these drugs bringtemporary relief to the arthritic patient but present the danger of sideeffects and the physican has to balance the potential benefit againstthe risks. However, arthritis reoccurs following withdrawal of suchchemical treatment. For many years rheumatoid arthritis was consideredto be an infection (Hollander et al., 1960; Robinson, 1967), but withthe advent of the concept of auto-immunity this idea lost favor. Such aview has recently been revived (Lancet, 1970, 2, 303) and is supportedby many observations. It is highly likely that the limax amoebae, foundin all the collagen and auto-immune diseases, may well be theaetiological agent of these conditions and that anti-protozoal drugs mayhelp by their action on these organisms.

The use of a bis-phenyl (2-halophenyl)-1-imidazolylmethane (e.g.clotrimazole) for the treatment of rheumatoid arthritis is disclosed inmy U.S. Pat. No. 4,073,922 issued on Feb. 14, 1978. The use oftinidazole and related compounds is disclosed in my U.S. patentapplication Ser. No. 813,922, filed July 8, 1977. It has also beensuggested to use a nitroimidazole derivative in the treatment ofrheumatoid arthritis in the Journal of Tropical Medicine and Hygiene v.75, p. 64 to 66, March 1972.

Various other anti-protozoal drugs were tried on cases of rheumatoiddiseases or of various localized manifestations of this. The substancesinvestigated were 4-aminoquinolines (chloroquine), hydroxychloroquine(plaquenil), amodiaquine (camoquin), copper sulfate and bile salts(dehydrocholine), which are effective in killing the trophozooites ofmany amoebae in the concentration found in the small intestine. All ofthese were actually shown experimentally to kill amoebae. In addition,other anti-protozoal drugs were also investigated. They include suramin,pentamidine, dehydroemetine (DHE or mebadin), metronidazole (flagyl),nimorazole (naxogin), phanquone (entobex) and diloxane (furamide).

The 4-aminoquinolines have been given orally in a dose of 200 and 400mg. daily, reduced after a month to 200 mg. twice weekly, care beingtaken to examine the eyes at intervals to guard against keratitis ormacular changes. Copper salts were administered as 25 mg. of coppersulfate in aqua chloroformi by mouth three times daily. This may producevomiting and/or diarrhea and the dose has to be decreased to 10 mg.three times daily. Only a small amount of the metal is absorbed,however, and no other side effects are observed even when taken overseveral months. Bile salts as dehydrocholine were given in a dose of500-1000 mg. three times a day by mouth. They may produce mild colic.Pentamidine was at first given by intramuscular injection into thebuttock in doses of 200 mg. daily for ten days. The course was repeatedtwice with intervals of seven days between. This substance is liable toproduce local necrosis or abscess formation. Pentamidine can be given bymouth, but the absorption is uncertain. Capsules containing 200 mg. wereespecially made and a dose of 200 mg. twice daily to 400 mg. three timesdaily by mouth were tried in various combinations. Suramin was given byintravenous injection of 500 mg. in 10 ml. of water and after this everyfour days 1 g. was injected until 10 g. had been given. The course wasrepeated once after four months. Dehydro-emetine (DHE) was given byintramuscular injection in doses of 60 mg. daily for ten days andrepeated after seven days, or 60 mg. three times daily by mouth for 7-10days, repeated after an interval of ten days. Before commencingtreatment E.C.G.'s were taken and repeated before each successiveinjection. Metronidazole (flagyl) was given in doses of 400 to 600 mg.three times daily by mouth and nimorazole (naxogin) in doses of 75 mg.three times daily. Phanquone (entobex) was given in doses of 100 mg.twice daily by mouth for seven days, repeated at intervals of a week,Diloxanide (furamide) was given in doses of 500 mg. three times dailyfor ten days and repeated once.

The various substances tested above were tried on cases of rheumatoidarthriris of varying severity, systemic lupus erythematosus,dermatomyositis and other manifestations of collagen and auto-immunedisease and observations made on the clinical condition, oedema, morningstiffness, E.S.R., plasma proteins, RF, ANF and organ-specificantibodies in the serum. No attempt at a double-blind trial was made asit became obvious, fairly early or even the day after commencingtreatment, whether beneficial results were obtained and furthermore,symptomatic improvement is associated with improvement or disappearanceof the abnormal blood changes, indicating that the drug was effectiveand improvement not due to suggestion. No beneficial effect was obtainedfrom flagyl, naxogin, entobex, suramine or furamide in the doses used.However, Abd-Rabbo et al. (1972), using a derivative of nitro-imidazoleBT 985 Merck A. G., which is active against amoebae, giardia andtrichomonas, obtained beneficial effects in one case of systemic lupuserythematosus and nine of ten cases of rheumatoid disease. The drug wasgiven in doses of 250 mg. daily for 14-39 days. In the follow up periodof 3-6 months no treatment was given and it was noted that the painrecurred, yet not to the same degree as before the treatment.

It has now been discovered that certain substituted imidazole compoundswhich have antiprotozoal activity are effective for treating rheumatoidarthritis and related collagen and auto-immune (rheumatoid) diseases.

The method of determining the anti-protozoal activity of drugs on limaxamoebae was described by Fulton, C. Methods in Cell Biology (edited byD. M. Prescott), p. 341, New York, 1070, and followed by Jamieson andAnderson in Lancet, 1974, 1, 261. All experiments were performed using5-day old 5 ml. cultures of amoebae in the axenic medium "A" of Fulton.A standard inoculum of 100 c.mm. of differing concentrations of amoebaewas added to each 1 ml. tube containing the dilutions of the compound tobe tested (dissolved initially in dimethyl sulfoxide) or other drugs inthe axenic medium. The tubes were incubated for 5 days at 37° C. and thefinal concentrations per c.mm. was compared with the initial count todetermine percentage kill.

The effective compounds have the general formula: ##STR1## wherein thenitro group is in the 4 or 5 position, R' is hydrogen, lower alkyl offrom 1 to 7 carbon atoms, or a halogen such as fluoro, iodo, chloro orbromo, and R is ##STR2## wherein n is a whole integer from 1 to 4 andmay be the same or a different number and X is halogen as describedabove, or ##STR3## wherein A is alkylene of 1 to 6 carbon atoms and R₁and R₂ are ethyl or when taken together, along the N-atom are morpholineor pyrrolidino. In these latter compounds a halogen can be in theposition not occupied by the nitro group and the pharmaceuticallyacceptable acid addition salts thereof. Particularly useful compoundsare when the nitro group is in the 5-position, R' is hydrogen or methyland R is either ##STR4## or CH₂ --CH(OH)--CH₂ --X wherein A and X are asdefined above. The preparation of these compounds are described in U.S.Pat. No. 3,435,049 issued Mar. 25, 1969 to Max Holler or U.S. Pat. No.3,399,193 issued Aug. 27, 1968 to Giraldi and Mariotti. In these patentsthe compounds are described as having activity for treating ofinfections due to pathogenic protozoa such as trichomonacides. Typicalexamples of suitable compounds for this invention are the following:

N-β-diethyl-amino-ethyl-5-nitro-imidazole

N-β-diethyl-amino-ethyl-4-nitro-imidazole

N-β-morpholino-ethyl-5-nitro-imidazole (nimorazole)

N-β-morpholino-ethyl-4-nitro-imidazole

N-β-pyrrolidino-ethyl-5-nitro-imidazole

N-β-pyrrolidino-ethyl-4-nitro-imidazole

1-(2,3-epoxypropyl)-4-iodo-2-methyl-5-nitro-imidazole

1-(3-chloro-2-hydroxypropyl)-2-methyl-5-nitro-imidazole (ornidazole)

1-(3-chloro-2-hydroxypropyl)-2-methyl-4-nitro-imidazole

1-(2,3-epoxypropyl)-2-methyl-4-nitro-5-iodo-imidazole

1-(2,3-epoxypropyl)-2-methyl-5-nitro-imidazole

1-(2,3-epoxypropyl)-2-methyl-nitro-imidazole

4-iodo-2-methyl-5-nitro-imidazole

5-iodo-2-methyl-4-nitro-imidazole

1-(3-chloro-2-hydroxypropyl)-5-iodo-2-methyl-4-nitro-imidazole

1-(3-chloro-2-hydroxypropyl)-4-iodo-2-methyl-5-nitro-imidazole

1-(3-chloro-2-hydroxypropyl)-2-iodo-4-nitro-imidazole

The salts of the compounds of the invention are the pharmaceuticallyacceptable non-toxic acid addition salts. Examples of suitable acids arethe hydrohalic acids (hydrochloric being preferred), phosphoric acid,mono- and bifunctional carboxylic acids, such as acetic acid, propionicacid, maleic acid, succinic acid, fumaric acid, tartaric acid, citricacid, salicylic acid, sorbic acid, lactic acid and1,5-napththalene-disulphonic acid. The hydrohalides, especially thehydrochlorides, lactates and salicylates are of particular value.

The diagnosis of active rheumatoid arthritis in cases treated wasconsistent with the criteria of the American Rheumatism Association. Thepatients were not hospitalized or confined to bed. The drugs they werebeing treated with when first seen were discontinued. Serialinvestigations were carried out before and repeated during and aftertreatment. Nimorazole (Naxogin) and Ornidazole (Tiberal) have a markedeffect in abolishing the symptoms and signs of active rheumatoid diseaseand have been used so far in 35 cases. In cases of trichomonas infectionor amoebiasis these drugs produced no generalized disturbance. Theiraction in this disease is generally to cause within a few hoursinfluenzal-like symptoms often with headache and sweating andgeneralized aching and an exacerbation of the pain, heat and swelling ofthe joints affected by active disease and in addition they may cause theappearance of inflammatory changes in previously unaffected joints or innon-articular tissues. These symptoms may be accompanied by a mildpyrexia and by sweating and last two to three days. This responseconstitutes an herxheimer reaction and suggests the drug was destroyingan organism sensitive to the drug. This occurs in about two-thirds oftreated cases. In the other one-third there occurs no exaggeration ofsymptoms. The treatment was begun with two 500 mgm. tablets and threedays later by a dose of four 500 mgm. tablets taken in one dose. Ifthere is no response to the treatment, this treatment is repeated atweekly intervals. Sometimes a reaction does not occur until severaldoses have been taken. If there is a reaction then the dosage is notrepeated until the reaction has died down. If the first administrationproduces a reaction, then after subsequent administration the generalrule is a gradual diminution in this response until it finallydisappears at which time treatment semimonthly. There is a gradualdisappearance of signs and symptoms of inflammatory activity in theaffected joints. Anaemia and raised ESR if present at the beginning isnot seen until about four weeks after cessation of treatment. Cases havenow been followed for up to a year without evidence of recurrence ofactive disease. Bony cartilaginous changes are, of course, notreversible but this form of treatment halts the progress of thecondition and in early cases all signs and symptoms of the diseasedisappear.

The therapeutically effective compound can be used either as such or incombination with pharmaceutically acceptable carriers. Suitable forms ofadministration in combination with various inert carriers are tablets,capsules, powders, aqueous suspensions, syrups and the like. In theaforesaid case, the therapeutically active compound should be present inthe total mixture at a concentration of about 0.5 to 90.0 percent byweight, i.e., in quantities which suffice to attain the range of dosagementioned above. Tablets may also contain fillers such as starch,avicel, lactose, or dicalcium phosphate together with various additivessuch as dyes and binders. Typical of such materials arepolyvinylpyrrolidine, methyl cellulose, geltin and the like. It isfurther required to add lubricants such as magnesium stearate, stearicacid or talc for producing tablets. Tablets can also be film coated.

A typical example for making a tablet is as follows:

EXAMPLE A

    ______________________________________                                                            Weight                                                    ______________________________________                                        Micronized imidazole compound                                                                         0.75   Kg.                                            Cornstarch powder       0.08   Kg.                                            Avicel (microcrystalline cellulose)                                             PH 102                0.27   Kg.                                            Methocel 50 HG, 60 CPS  15.00  gm.                                            Purified water        q.s.                                                    ______________________________________                                    

The imidazole compound is mixed in a suitable blender with the othercomponents and then granulated mass is passed through an oscillatorequipped with a 20-mesh screen. The granules are dried in an aircirculating oven at 50° C. until a moisture content of less than 3% isreached. The granules are screened through a 20-mesh screen, lubricatedwith steric acid and mg. of magnesium stearate. The final mix iscompressed into tablets of 750 mg. each, which contain 500 mg. of theimidazole compound per tablet and can be used for oral administration.

Any departure from the foregoing description conforms to the presentinvention is intended to be included within the scope of the claims.

What is claimed is:
 1. A method for producing remission in patientssuffering from active rheumatoid arthritis which comprises orallyadministering to such a patient an effective amount of a compound of theformula: ##STR5## wherein R' is hydrogen or lower alkyl having from 1 to7 carbon atoms, A is alkylene of from 1 to 6 carbon atoms, and R₂ and R₃are ethyl or taken together with the N-atom is morpholino and the nitrogroup is in the 4 or 5 position.
 2. The method of claim 1 wherein insaid compound A is alkylene having from 1 to 6 carbon atoms, R' ishydrogen, the nitro group is in the 5-position and the ##STR6## group ismorpholino.
 3. The method according to claim 2 wherein the compound isnimorazole.
 4. The method of combating rheumatoid arthritis of claim 3which comprises orally administering to the infected patient the subjectcompound in doses of approximately 20 mg. to about 50 mg. per Kilogramof body weight daily, every other day or once weekly.
 5. The method ofclaim 4 which comprises orally administering to the infected patient aweekly dose amount of about 1.0 g. to about 3.0 g.